3,4'-Dideoxymycaminosyltylonolide and salts thereof exhibit an antimicrobial activity on Gram-positive and Gram-negative microorganisms, and they are usable as antimicrobial agents having particularly excellent effect of protection from an infection [see Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") No. Hei 2-275894].
3,4'-Dideoxymycaminosyltylonolide can be produced by protecting functional groups of mycaminosyltylonolide which is an acid hydrolyzate of tylosin, then converting the hydroxyl groups at the 3-position and 4'-position into deoxy groups and further removing the protecting groups. For converting the hydroxyl group at the 4'-position into deoxy group, a known process can be employed, such as a process wherein the hydroxyl groups at the 3-position and 4'-position are sulfonylated, then the hydroxyl group at the 4' position is halogenated by a method described in J. Antibiotics 34, pages 1374 to 1376 or J. P. KOKAI No. Hei 2-191295 and the halogen atom is removed by reduction with tributyltin hydride. The sulfonic acid can be eliminated from the hydroxyl group at the 3-position to form a double bond, which is catalytically reduced to form the deoxy compound.
However, the above-described process for producing 3,4'-dideoxymycaminosyltylonolide has a defect in that the yield of the intended product is low, since the conversion of the hydroxy groups at the 3-position and 4'-position into deoxy group necessitates the following steps: sulfonylating both hydroxyl groups; halogenating the hydroxyl group at the 4'-position and removing the halogen atom by reduction with tributyltin hydride; and forming double bond elimitating sulfonyloxy group at the 3-position and reducing the double bond. In addition, tributyltin hydride used for forming the deoxy group at the 4'-position has an offensive odor to make the purification of the reaction product difficult. Thus problems are posed when this reaction is employed on an industrial scale.
Therefore, the object of the present invention is to provide a useful intermediate for producing 3,4'-dideoxymycaminosyltylonolide. Another object of the present invention is to provide a process for efficiently converting the groups at the 3- and 4'-positions into deoxy group.